Karlsruhe–Basel high-speed railway

The Karlsruhe–Basel high-speed railway (Ausbau- und Neubaustrecke Karlsruhe–Basel, literally "Upgraded and new line Karlsruhe–Basel") is a new line being built on the route of the Mannheim–Karlsruhe–Basel railway (Rhine Valley Railway). As a result of the project, the railway through the Rhine Valley is being upgraded to four continuous tracks and its operational efficiency will be increased as a result of the segregation of the various transport flows. The travel time for passenger services between Karlsruhe and Basel is to be shortened by 31 minutes. The project forms part of the Rotterdam–Genoa corridor and part of it is also part of the Main line for Europe (Magistrale für Europa in German and Magistrale européenne in French; Paris–Budapest).

Large parts of the line runs next to the existing Rhine Valley Railway. The planning of the line has been carried out progressively since the mid-1980s and the first section of the line between Rastatt Süd and Offenburg, was placed in operation in 1993. While several sections have been opened others are under construction or not started. The main components of the projects include the Rastatt Tunnel, the Katzenberg Tunnel and a western bypass of Freiburg for freight.

The date of the completion of the overall project is uncertain. The Federal Government considers a completion by 2030 possible. Planning services for sections 7.2. to 7.4 have been procured on the basis that it will be completed by the end of 2042.

The planned total cost is €6.172 billion (as of April 2013). Until the end of 2014, €2.27 billion had been spent on it. Deutsche Bahn estimated the total cost in 2015 as being €7.1 billion.